FIELD OF THE INVENTION
The invention relates to a method for disposing of an aqueous solution that contains an organic acid and an iron complex and occurs particularly in the decontamination of radioactively contaminated surfaces of components. The invention also relates to a device for disposing of an aqueous solution, having a container for the solution that contains an organic acid and an iron complex and occurs particularly in the decontamination of radioactively contaminated surfaces of components.
A method and a device for disposing of an organic substance are known from German Patent Disclosure DE 41 26 971 A1. With this method and the associated device, organic acids that have been used in surface decontamination of radioactively contaminated components are treated.
After such decontamination, a solution remains that contains not only the acid portion, which is chemically unchanged, but also chemicals formed in the decontamination as well as radioactive substances removed from the component surface.
In order to make do with the smallest possible final storage vessel, the attempt is made to reduce the volume of the solution before its immobilization.
It is known to feed hydrogen peroxide to the solution while the solution is in contact with a catalyst. The essential products of decomposition are then carbon dioxide and water. The concentration of the solution is reduced as a result, so that after an evaporation step only a relatively small volume remains that has to be immobilized and delivered to a final storage vessel.
The known method and the associated device, to dispose of the organic substance, require a catalyst. Such a catalyst must be put into contact with the substance. To that end, solid catalyst material must be held in suspension in the solution to be disposed of. A variant of this requires a complicated and expensive mounting for the catalyst.
During decontamination, metals in anionic and cationic form occur. For removing these metal ions, it is usual to use anion and cation exchangers. With an anion exchanger, anionic metal complexes and also decontamination chemicals are removed. This requires a large anion exchanger. This produces a large quantity of ion exchange resin that has to be disposed of.
The remaining solution is as a rule concentrated by evaporation, and the resultant concentrate is put in final storage. The decontaminated system is then flushed as well, and the flushing water is evaporated. Accordingly, very large quantities of solution or water must be treated.